Amazon has announced it is taking on the pharmaceutical market with the acquisition of online pharmacy PillPack, a move that promptly rattled pharmacy stocks and dealt a major blow to the country’s top pharmacies. Amazon reportedly beat out Walmart and paid about $1 billion for the company, which is licensed to ship drugs in all 50 states. “PillPack’s visionary team has a combination of deep pharmacy experience and a focus on technology,” Jeff Wilke, Amazon’s CEO of consumer business, said in a statement. “We’re excited to see what we can do together on behalf of customers over time.” The move gives the online retail giant a leg up in the $560 billion prescription drug industry. News of the deal has already put an $11 billion dent in the market value of drugstores including Walgreens Boots Alliance, CVS Health, and Rite Aid.